Diabetes Glossary

We’ll add definitions of medications to this glossary as soon as we discuss medications in a future publication in this series of diabetes books.

A1c test: a highly useful tool for monitoring blood glucose levels; has become a primary screening and diagnostic test for prediabetes (5.7%–6.4%) and for types 1 and 2 (≥ 6.5%), but not for gestational diabetes or type 1 in children; normal values are < 5.7%

Absorption (digestive): the passage of the end products of digestion from the intestine into the blood

Accelerometer: a device that senses change in movement, speed, or direction

Aerobic exercise: activities that use the large muscles, leading to a more rapid heartbeat and increased blood flow to muscles; examples include walking, biking, and swimming

Amylin: a hormone secreted by beta cells in the pancreas; helps lower blood glucose in two ways: 1.) by slowing the emptying of the stomach, thus helping to regulate the timing of glucose release into the bloodstream after eating; 2.) by blocking secretion of glucagon, a hormone that raises blood glucose levels

Arteriosclerosis: a group of diseases, including atherosclerosis, of the medium or large arteries, characterized by thickening, hardening, and loss of elasticity of the arterial walls (see Atherosclerosis entry) 

Atherosclerosis: a type of arteriosclerosis (thickening, hardening, and loss of elasticity of the arterial walls) characterized by plaque formation inside and on the walls of the arteries, causing narrowing, and possibly clotting and blockage, potentially resulting in heart attack or stroke 

Atherosclerotic cardiovascular disease: in 2016 the American Diabetes Association changed the term “cardiovascular disease” (CVD) occurring in diabetes to “atherosclerotic cardiovascular disease” (ASCVD), a more specific term 

Autoimmune disease: a disorder in which the immune system attacks and destroys body tissues it mistakenly considers foreign

Basal insulin: 1.) insulin normally produced throughout the day and night, keeping the body cells supplied with energy; 2.) in diabetic patients, a long-acting insulin taken once or twice daily to maintain blood glucose levels between meals and during sleep

Body mass index (BMI): an index number used to categorize people as underweight, normal weight, overweight, or obese; calculated by measuring a person’s height and weight, and entering the values into a formula or calculator, or consulting a table

Bolus insulin: 1.) insulin normally produced in response to a meal, bringing blood glucose levels back to normal range; 2.) in diabetic patients, a rapid-acting insulin taken a short time before meals to control the rise in blood glucose levels resulting from digestion and absorption of glucose from food; the amount administered depends on the amount of carbohydrate eaten

Carbohydrates (sugars, starches, and fiber): nutrients contained in vegetables, fruits, beans, grains, pasta, and breads; one of the three types of nutrients the body turns into energy; the others are proteins and fats

Cardiometabolic: pertaining to heart disease and a co-existing metabolic disorder, such as diabetes

Cardiovascular disease: disease of the heart or blood vessels (arteries, capillaries, and veins) (see Atherosclerotic cardiovascular disease) 

Carrier protein: a compound that escorts glucose and sodium together from the bloodstream to the inside of the cells; carrier proteins in some tissues, such as muscle and fat cells, require insulin to help escort glucose inside the cells; glucose can enter the liver and the brain without the help of insulin

Central obesity: extra fat around the waist, creating a “pot-belly” or “beer-belly” shape; a combination of subcutaneous fat (fat under the skin) and visceral fat (fat surrounding the internal organs); a key risk factor for the metabolic syndrome

Cholesterol: a fat-like substance produced mostly in the liver, but some is obtained from food; the body requires cholesterol for many functions (see High-density lipoprotein cholesterol and Low-density lipoprotein cholesterol)

Complex carbohydrates: nutrients composed of chains of simple sugar molecules; sometimes called “good” carbohydrates, they take longer to digest than sugars; examples include whole grains, carrots, and potatoes

Continuous glucose monitoring systems: devices consisting of sensors, transmitters, and readers that display data; designed to monitor blood glucose levels almost constantly

C-peptide: a byproduct of insulin production by beta cells in the pancreas; C-peptide levels are an indication of how much insulin the pancreas is producing

C-peptide test: a test that can help differentiate between type 1 and type 2 diabetes; normal levels of C-peptide suggest that the pancreas is also producing normal levels of insulin, but the body is not responding properly to the insulin—an indication of type 2; low levels of C-peptide suggest that insulin production also is too low, or is absent—an indication of type 1

Dehydration: excessive loss of body fluid; occurs when the body loses more fluid than it takes in

Diabetes insipidus: a disease usually caused by lack of a hormone (vasopressin) produced by the pituitary gland; people with diabetes insipidus secrete large amounts of urine, but the urine is sugar free

Diabetes mellitus: a disease of carbohydrate, protein, and fat metabolism, caused by lack of insulin or inability of the body to use insulin effectively; characterized by high blood glucose levels (hyperglycemia) and other metabolic disorders

Diagnostic test: a medical procedure performed to determine the presence, type, or severity of a medical condition, and to develop a treatment plan; examples include laboratory tests and imaging procedures

Enzyme: a protein that is created by an organism and speeds the rate at which reactions occur, without undergoing any changes itself

Essential amino acids: amino acids the body cannot manufacture on its own, thus must obtain from dietary sources; people whose diet lacks animal proteins need to eat a variety of plant proteins to obtain enough essential amino acids

Essential fatty acids: fatty acids the body cannot manufacture on its own, thus must obtain from dietary sources; examples are linoleic acid and linolenic acid, found in fats

Fasting plasma glucose (FPG) test: a test used to determine the glucose level after a person has fasted for 8 to 12 hours; used to screen for and diagnose prediabetes (as impaired fasting glucose) (100–125 mg/dL) and diabetes (≥ 126 mg/dL); normal FPG levels are < 100 mg/dL

Fats: nutrients contained in oils, butter, margarine, cream, and chocolate; one of the three types of nutrients the body turns into energy; the other two are proteins and carbohydrates

Fiber: carbohydrates that are not digested; classified as soluble or insoluble; foods containing soluble fiber include legumes (eg, beans, peas, lentils, and peanuts), fruit, some vegetables, and oat bran; foods rich in insoluble fiber include whole grain cereals and some vegetables

Fructose: a very sweet sugar; the principal sugar in fruit

Gestational diabetes: a condition in which women who have never had diabetes develop, during pregnancy, the high blood glucose levels characteristic of the disease; levels usually return to normal after the baby is born, but these mothers have more than a seven-fold risk of developing type 2 diabetes five to 10 years after giving birth

Glucagon: a hormone secreted by alpha cells in the pancreas; glucagon raises glucose levels in the blood between meals or during exercise; it does so by stimulating the liver to release stored glucose; an injectable form of glucagon is available by prescription to treat dangerously low blood glucose levels (hypoglycemia)

Glucose: a simple sugar, glucose is the main type of sugar in the blood, the main source of energy for the body cells, and the only sugar the cells can use as a rapid energy source; table sugar is a molecule of glucose joined chemically to a molecule of fructose; the body splits the molecule, converts the fructose to glucose, and uses the glucose for energy; the term dextrose, a former name for glucose, currently is used to refer to glucose solutions given intravenously to replace fluids or nutrients

Glucose uptake: the passage of glucose from the blood into the cells; glucose cannot enter body cells by absorption, because it needs the help of a carrier protein to cross a cell membrane

Glycated (glycosylated): sugar coated

Glycated (glycosylated) hemoglobin: a form of hemoglobin that binds with glucose; abbreviated as A1c, A1C, or HbA1c

Glycemic index (GI): a measure of how quickly blood glucose levels rise after one gram of a particular food is eaten, compared to eating one gram of pure glucose, which has a GI of 100; foods that release glucose rapidly have a high GI, while those that are broken down more slowly, such as whole grain foods, have a low GI; a drawback of the GI is that it does not take into account the amount of the food actually eaten

Glycemic load (GL): an estimate of how quickly a given amount of a particular food will spike blood glucose levels; calculated by multiplying the glycemic index of the food by the total amount of carbohydrate in the serving; for example, a 100-gram serving of carrots has a glycemic index of 47 and a carbohydrate content of 7.5%; multiplying the two gives a glycemic load value of 3.5

Glycosuria: the presence of glucose (sugar) in the urine

Hemoglobin (Hb or Hgb): a pigment that gives red blood cells their color; hemoglobin carries oxygen from the lungs to cells in the rest of the body

High-density lipoprotein cholesterol (HDL-C): known as “good” cholesterol, HDL is the portion of cholesterol in the body that circulates in high-density lipoprotein particles; HDL carries “bad” cholesterol (LDL) from the bloodstream back to the liver, to be broken down for removal from the body; very low HDL levels indicate high risk of cardiovascular disease; high HDL levels have a protective effect

High-fructose corn syrup (HFCS): a commercial product made from cornstarch; contains roughly equal amounts of glucose and fructose, and is used as a sweetener in sodas, fruit-flavored drinks, and processed foods; some researchers are concerned about a possible link between HFCS and obesity and other conditions

Hormone: a chemical produced by a gland in one part of the body and released into the blood; has effects on or regulates important functions elsewhere in the body

Hydrogenated oils: polyunsaturated fats changed chemically to be more like saturated fats; hydrogenation causes the fat to be more solid at room temperature

Hyperglycemia: high blood glucose levels; usually defined as > 180 mg/dL when measured after a meal; can occur in people with type 2 diabetes when the balance between food intake and activity (and medication, if any) needs to be adjusted; often accompanied by sugar (glucose) in the urine, frequent urination, and increased thirst

Hypertension: high blood pressure; recently redefined by the American Heart Association and the American College of Cardiology as ≥ 130/80 mm Hg (millimeters of mercury); normal is now considered < 120/80 mm Hg

Hypoglycemia: low blood glucose levels; levels < 70 mg/dL may be accompanied by nervousness, hunger, and confusion; treated with a carbohydrate-rich food, such as juice or glucose tablets, or by an injection of glucagon, if the person is unconscious

Iliac crest: the curved upper edge of the hip bone (ilium), the largest bone of the pelvis; the ridge can easily be felt near the level of the navel, on either side

Impaired fasting glucose (IFG): a fasting glucose level of 100–125 mg/dL; prediabetes

Impaired glucose tolerance (IGT): a plasma glucose level of 140–199 mg/dL at the 2-hour point of an oral glucose tolerance test; prediabetes

Incidence: the number of cases of a disease diagnosed during a certain period, such as “1.9 million new cases of diabetes were diagnosed in people aged 20 years and older in 2010”

Insulin: a hormone secreted by beta cells in the pancreas; enables glucose to enter the body cells, where the glucose is used for energy or stored, thus lowering glucose levels in the blood

Insulin receptor sites: places on cell walls where insulin binds, allowing glucose to enter the cell

Insulin resistance: a condition in which the body cannot use its insulin effectively; thought to be due to too few insulin receptors on the cell walls, or to an inability of the receptors to manage insulin normally, or both; insulin resistance is linked to certain genes, and to physical inactivity and excess body weight; usually it is present before type 2 diabetes develops

Ketones: waste products formed when fats are broken down for energy; if ketone levels in the blood and urine become very high—a condition called ketoacidosis—nausea, vomiting, and coma can result

Kinesiology: the scientific study of human movement as it relates to physical activity, health, and disease prevention

Latent autoimmune diabetes in adults (LADA): thought to be a slowly progressing variation of type 1 diabetes, but often is misdiagnosed as type 2; sometimes called type 1.5 diabetes; accounts for about 10% of diabetes cases

Lipid: a term for fat in the body; lipids are fatty substances that are a main structural component of living cells, along with carbohydrates and proteins; dietary lipids consist mostly of fat (triglycerides), phospholipids, and cholesterol, and are broken down by the body and used for energy

Low-density lipoprotein cholesterol (LDL-C): known as “bad” cholesterol; the portion of circulating cholesterol carried in low-density particles; although LDL carries cholesterol in the blood to cells where it is needed, it can also deposit cholesterol in the arteries, causing atherosclerosis and increasing the risk of heart attack or stroke; LDL levels that are very high indicate a high risk of cardiovascular disease

Maturity onset diabetes of the young (MODY): a condition caused by a genetic defect; accounts for about 5% of diabetes cases

Metabolic disease: a disorder that disrupts the processes in which the cells, fluids, and chemicals of the body use food for energy, growth, healing, and other body functions

Metabolic syndrome: a group of factors, eg, insulin resistance and central obesity, that tend to occur together, and are associated with, or increase the risk of, prediabetes, type 2 diabetes, and cardiovascular disease (“syndrome” means group of symptoms or risk factors)

Metabolism: pertaining to the various processes in which the body’s cells use fluids and chemicals of the body as food for energy, growth, healing, and other functions; often used to refer specifically to the breakdown of food and its transformation into energy

mg/dL: milligrams per deciliter, a standard measurement used in the U.S. for lab test results; there are 5 to 20 granules of typical table sugar in a milligram, and a deciliter is about 3 ounces of water

mmol/L: a measurement used by some countries outside the U.S. to report lab test results; to convert mmol/L to mg/dL, multiply by 18

Monounsaturated fats: “good” fats, found in olive oil (a staple of the Mediterranean diet), canola oil, peanut oil, and high-oleic safflower and sunflower oils

Nanogram: one billionth (1/1,000,000,000) of a gram, written as ng; in contrast, a milligram, which is one thousandth of a gram, is equal to between 5 and 20 granules of table sugar

Oral glucose tolerance test (OGTT): a test to screen for and diagnose prediabetes (as impaired glucose tolerance) (140–199 mg/dL at 2 hours, after drinking a glucose solution); types 1 and 2 (≥ 200 mg/dL at 2 hours); and gestational diabetes; normal levels at 2 hours are < 140 mg/dL

Plasma: the liquid (clear) part of the blood, in which blood cells, platelets, and other particles are suspended

Polycystic ovary syndrome: a common hormonal disorder in women; may involve small cysts on the ovaries, excess hair growth, weight gain, and difficulty losing weight

Polydipsia: increased thirst, with high fluid intake

Polyphagia: increased appetite, with high food intake

Polyunsaturated fats: fatty substances contained in corn oil and other oils that generally are liquid, even if refrigerated; considered “good” fats because they have many health benefits when used to replace saturated fats; the two main types, omega-3 fats and omega-6 fats, are essential fatty acids, meaning the body needs them but cannot manufacture them

Polyuria: high urine production, usually with frequent urination

Prediabetes: a condition in which blood glucose levels are higher than normal, but below the range of diabetes; also known as impaired glucose tolerance, or impaired fasting glucose, depending on the diagnostic test used; most people with prediabetes do develop type 2, but the progression often can be prevented by weight loss and lifestyle changes

Prevalence: the number of cases of a disease that exist in a given population, such as, “29 million children and adults in the U.S. have diabetes”

Proteins: nutrients composed of amino acids and found in meat, fish, eggs, and some dairy products; non-animal sources of protein include beans, nuts, seeds, soybeans (soy milk, tofu, and miso), textured vegetable protein (TVP), and avocados; proteins are one of the three types of nutrients the body turns into energy; the other two are carbohydrates and fats

Random plasma glucose (RPG) test: a diagnostic test that does not involve fasting and is not recommended for diabetic screening; typically performed in a hospital emergency department or doctor’s office when a patient has classic symptoms of diabetes; often doctors order a different test for confirmation

Reabsorption: the return into the circulation of glucose, sodium, and other substances, after they have been secreted into the urine by the kidney tubules

Renal threshold: the level at which the kidneys respond to high glucose levels by excreting glucose into the urine, instead of recycling it back into the blood; the renal threshold varies widely, but usually corresponds to a blood glucose level of about 180 mg/dL

Resistance training: activities in which the muscles contract against resistance from free weights or machines; the goal of resistance training is to increase muscle mass, strength, and muscle tone

Risk factor: a characteristic or condition that increases the likelihood that a given disease will develop

Saturated fats: unhealthful fats that come mainly from animal sources; can raise LDL and total cholesterol levels

Screening test: a medical procedure performed in someone who is at risk of a specific disorder, but doesn’t necessarily have, or may not be aware of, any symptoms or signs associated with that disorder; a positive result on a screening test suggests the need for a diagnostic test; the goal of screening is early identification of those who may need treatment

Self-blood glucose monitoring (SBGM): a procedure for measuring glucose levels in whole blood; in contrast, lab tests usually measure glucose levels in plasma

Sensitivity: the ability of a test to identify patients who have a given disease or condition, such as diabetes

Simple carbohydrates: nutrients consisting of just one or two sugar molecules; simple carbohydrates are rapidly digested, and represent the quickest source of energy; table sugar is an example

Somatostatin: a hormone secreted by delta cells in the pancreas; somatostatin plays a minor role in fine-tuning blood glucose levels; it inhibits the release of insulin or glucagon, thus raising or lowering blood glucose levels

Specificity: the likelihood that an abnormal test result will occur only in patients who actually have the disease or condition they are being tested for

Starches: nutrients composed of units of glucose; known as complex carbohydrates; the main type of stored energy in plants, especially wheat, corn, rice, and potatoes

Sucrose: table sugar, obtained commercially from sugarcane and sugar beets; consists of a molecule of glucose joined chemically to a molecule of fructose; the body splits the molecule, converts the fructose to glucose, and uses the glucose for energy

Sugars: the building blocks of carbohydrates; sweet, crystalline substances obtained from various plants, such as sugarcane and sugar beet; examples are glucose, fructose, and sucrose

Syndrome: a group of symptoms or risk factors for a specific disease

Trans fats (trans fatty acids): fats created by turning liquid oils into solids through a process known as hydrogenation; trans fats increase the shelf life of oils, and are found in vegetable shortenings and in some margarines, crackers, cookies, and snack foods; intake of trans fatty acids can increase LDL (“bad cholesterol”) levels and decrease HDL (“good cholesterol”) levels; most trans fats in the diet come from processed foods made with hydrogenated oils (polyunsaturated fats changed chemically to be more like saturated fats)

Triglycerides: a form of fat that accounts for most of the fat in the body; triglycerides are produced in the body and obtained from food; people who are overweight or have a diet high in saturated fats and trans fats usually have high triglyceride levels, thus are at increased risk of cardiovascular disease

Type 1 diabetes: a metabolic disease characterized by high blood glucose levels, due to total or virtual lack of insulin; typically develops when the body’s immune system destroys the insulin-producing beta cells of the pancreas, but rarely results instead from a genetic defect; develops most often during childhood, but can occur in adults

Type 2 diabetes: a metabolic disease characterized by high blood glucose levels, due to either a lack of insulin or the body’s inability to use its insulin effectively; excessive or inappropriate secretion of glucagon also plays a role; type 2 develops most often in adults, but is becoming increasingly common in children and adolescents, because of obesity

Ventilatory threshold: the point during exercise when carbon dioxide release starts to exceed oxygen intake, and the lactic acid content in muscles is greatly increased

Visceral fat: fat surrounding the internal organs; excess amounts are a key risk factor for the metabolic syndrome; extra fat carried around the waist is made up of both visceral fat and subcutaneous fat (fat under the skin)

Whole grain: pertains to foods that contain all the essential nutrients of an entire grain seed—bran, germ, or endosperm; a whole-grain product is labeled “100% whole wheat” (or rye, or other grain), with the grain listed as the first ingredient